Form Filling with Self-Compacting Concrete

The overall subject of this project was Self-Compacting Concrete. More specifically it has been to establish a modelling approach for prediction of the form filling behaviour of SCC in a vertical formwork. Self-Compacting-Concrete (SCC) was first introduced in the 1980s. The purpose was to obtain flow properties which would make it possible to cast into a formwork without the need for subsequent compaction, e.g. by using poker vibrators. The possibility of not having to carry out vibration should encourage a wide use of SCC due to the prospects of improving the structural quality, working environment, productivity, and architectural appearance. However, especially in vertical applications there is a great unused potential. Controlling the casting process is important in many different industries such as the metal, plastic, and food industry. The casting process may have a significant influence on the finished product and the challenges vary depending on the material characteristics and the type of flow. Concrete may be regarded as a suspension defined as particles dispersed in a matrix phase. When the particles remain homogeneously distributed during form filling the important form filling characteristics comprise the form filling ability and flow patterns. The form filling ability describes the ability of the material to flow out into every corner of the formwork, and the flow patterns describe the intrinsic flow characteristics of the homogeneous flow, e.g. the direction and rate of flow at every point and time during placing, which may have a significant influence on the heterogeneous flow phenomena. The heterogeneous flow phenomena comprise so-called blocking and dynamic segregation. Blocking refers to the situation where the flow of aggregates is disturbed by their interaction with the reinforcement bars, which may result in severe accumulation of the aggregates. Dynamic segregation refers to the situation, when particles segregate during flow. Compared to blocking, dynamic segregation is not caused by particle interactions with the solid boundaries, but it gradually evolves during flow over a larger scale of time and length. Any change in the particle volume fraction affects the local effective properties of the suspension and thus poses a threat to any process relying on flow of a homogeneous material. In order to obtain a satisfactory form filling and thereby a satisfactory structural quality, it is necessary to develop theoretical tools to predict form filling with SCC. Trial and er-